A wide variety of portable shelter frame constructions are known. Expositions of such constructions are contained in U.S. Pat. Nos. 3,424,178; 3,270,755; 2,922,653; 2,840,400 and 2,835,262. Such types of construction are employed to shelter automobiles, boats, aircraft and the like, or even as warehouses for equipment and other items. While most of the known constructions are useful for their claimed functions, many exhibit drawbacks with respect to their complexity, stability and strength. There exists, therefore, a need for a portable shelter frame structure which is simple, has good stability and strength. The present invention fulfills such a need.